How the Roman solidus continued as the Byzantine nomisma, what later writers meant by “bezant,” and how the coin's weight and design changed.
The solidus was a Roman gold coin introduced under Constantine in the fourth century. In the Byzantine period its continuation was known in Greek as the nomisma; bezant is a later Western name for Byzantine gold coinage, not a synonym used uniformly in every period.
A British Museum solidus of Constantine illustrates the coin's early form. Its gold standard was long-lived, but weight and fineness changed over time; it was not an unchanged 700-year guarantee.
The "Bezants" of Global Commerce
Byzantine gold coinage was used beyond the imperial capital and became familiar to neighbouring peoples. The name bezant appears in Western usage for Byzantine gold, but it does not tell us what every contemporary user called the coin.
Its reputation for a stable gold standard helped the coin remain recognisable across changing political and commercial boundaries.
Religious Artistry and Scyphate Cup Shape
Imperial portraits and religious imagery changed over the centuries. Under Justinian II, Christ appeared on some gold issues, a notable departure from the earlier ruler portrait shown on Constantine's solidus.
Some later Byzantine gold coins were concave, or cup-shaped; this later form should not be mistaken for a defining feature of Constantine's solidus.
The solidus and its Byzantine successor show how a denomination can persist while its name, standard and design evolve.